Catalysts for polymerizing and copolymerizing olefins have been known and are widely used in industry. The catalysts of this invention have many superior properties over prior catalysts in that they are adaptable to low pressure, vapor phase, solution form or, most importantly, particle form processes of polymerizing. When used in a continuous particle form ethylene polymerization process, these catalysts display excellent melt index control of resulting polymers and copolymers because of their extraordinary sensitivity to hydrogen.
This extraordinary sensitivity to hydrogen can in part be achieved by adjusting the concentrations of catalyst components on the support while maintaining a constant molar ratio between them. As a result, polymers and copolymers can be produced within a preselected melt index range.
The most important prior art of which Applicant is aware is U.S. Pat. No. 2,981,725 which describes the use of silica as a finely divided support for Ziegler-type catalyst compounds.
Another U.S. Pat. No. 4,173,547 which discloses the use of alumina and silica as such a support.
French Demande No. 2,406,643 discloses a polyethylene catalyst comprising a reaction product of dibutylmagnesium, ethylaluminum sesquichloride and tetraisopropyl titanate.
U.S. Pat. No. 4,173,547 discloses the use of a dibutylmagnesium with alumina or silica in a polymerization catalyst.
German Offen. No. 2,523,165 discloses a catalyst prepared by the reaction of a dibutylmagnesium/triethylaluminum complex with n-octanol to form another complex which is treated with titanium tetrachloride.
U.S. Pat. No. 3,642,746 discloses complexing of anhydrous metal halides with alcohols prior to reaction with titanium tetrachloride. The resulting catalysts are used for .alpha.-olefin polymerization.
U.S. Pat. No. 4,170,567 discloses the reaction product of titanium tetrachloride with an alcohol which then is reacted with a magnesia to provide a polymerization catalyst.
U.S. Pat. No. 4,105,585 discloses a process for making a Ziegler catalyst by reacting magnesium metal and a halogen-containing titanium compound in the presence of an alcohol.
U.S. Pat. No. 4,087,380 is similar to U.S. Pat. No. 4,105,585 except that the components are deposited on magnesia.